1. Field of the Invention
The present invention relates to adhesives and, more specifically, to a shape memory based reversible adhesive that is soft.
2. Description of the Related Art
The development of adhesives with varying properties and strengths has enabled the choosing of an adhesive to directly meet the needs of a given application. For example, a particular application may need a certain bond strength, a given thermal stability, or a prescribed rigidity. In classifying adhesives, categories based on adhesive type can be used; thermosetting, pressure sensitive, and contact adhesives are among the present categories, and each type has limited applicability. Nature, namely geckos, frogs, and insects, have inspired the development of adhesive systems with the ability to switch between an adhesive state and a non-adhesive state, referred to as reversible adhesives that can controllably debond from the adhering surface. Such semi-permanent cohesion provides versatility not provided by traditional adhesives. For example, using a reversible adhesive in place of a permanent adhesive enables simple disassembly of structures for part repair or replacement.
Conventional reversible adhesives may be made from shape memory polymers, which are polymers with the ability to fix a temporary shape, while memorizing their permanent form. The deformed SMP can indefinitely hold the temporary shape. Activation via an external stimulus, such as heat, light, electricity, or magnetic fields triggers recovery back to the permanent shape. SMPs are relatively rigid in their fixed states, however, due to the need for a switching mechanism to lock in the temporary shape.
As a result, reversible adhesives made with shape memory polymers may only be used on planar surfaces. Accordingly, there is a need in the art for a reversible adhesive that is soft and can conform and adhere to curved or textured surfaces as well as flat surfaces.